In an organic electroluminescence (EL) element, when a current is made to flow in a conductive organic light-emitting layer, electrons and holes injected into the organic light-emitting layer are recombined, and an organic light-emitting material that constitutes the organic light-emitting layer is made to emit light during the recombination. To make a current flow in the organic light-emitting layer and draw light outside, a transparent electrode and an opposite electrode are provided on both sides of the organic light-emitting layer. More specifically, the organic EL element is generally configured by forming a transparent electrode layer on a transparent substrate, forming organic light-emitting medium layers on the transparent electrode layer, and forming an opposite electrode layer on the organic light-emitting medium layers, and the transparent electrode is used as a positive electrode, and the opposite electrode is used as a negative electrode.
The organic light-emitting medium layers are formed by stacking a plurality of laminate-structured layers, and the organic light-emitting layer made of an organic light-emitting material is included in the plurality of the laminate-structured layers. In addition, for example, a hole-transporting layer, a hole-injecting layer, an electron-transporting layer and the like are included.
Recently, the organic light-emitting layer and the hole-transporting layer in the organic light-emitting medium layer have been formed of a polymer material that has a large weight-average molecular weight and is easily dissolved in a solvent. Thus, the respective layers can be formed using a wet coating method such as a spin coating method or a printing method such as a relief printing method, a letterpress reverse offset printing method or an inkjet method in the atmosphere, and the reduction of manufacturing facility costs or the improvement of productivity can be achieved (see PTL 1 to 4). Particularly, the relief printing method using a photosensitive resin plate containing rubber or other resins as principal components can produce the high-definition patterning of organic light-emitting medium layers at a uniform film thickness in an excellent manner without causing damage to an object being transferred (refer to PTL 5). In addition, there is a method in which polystyrene or polyvinyl carbazole is used as a viscosity adjuster for the polymer material (refer to PTL 6).